Near surface fluorescence and optical scattering profiles at CTD sampling stations. Cruises DP01 and DP02 from May 2015 - August 2015

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Publication Date




Funding Source


Data Collection Period

2015-05-02 to 2015-08-21


Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC)




Optical absorption and scattering are the primary determinants of the flow of radiant energy in the ocean’s surface waters. Particles in the water are the principle source of scattering, and the scattering measurements can indicate the amount and/or type of particles present. While a complete measurement of the scattered light field is complex and cumbersome, a measurement of the backscattering at particular angles can usually be related to the total backscattering of light. The backscattering of light not only provides information about the particle present, it is important for understanding variations in Rrs. Backscattering in the water was measured with a Hobilabs HS6 6 channel scattering meter. This viewed backscattered light at wavelengths of 442, 488,532,589,620, 680nm, and at a viewing angle of ~140°. The HS6 was synchronized with a chlorophyll and CDOM fluorometer, and both instruments were lowered on an instrument frame through the upper portion of the water column to obtain vertical profiles of the in situ chl. and CDOM fluorescence, as well as the amount and spectral shape of the backscattering. These profiles were at the CTD sampling stations, but instrument constraints limit the depth of the profiles to 200m or less. This data was collected during the same cruise as GRIIDC CTD datasets R4.x257.230:0004 and R4.x257.230:0010


The combination of in situ backscattering and fluorescence measurements can be used to examine the amount and type of particles is the water column. Profiles of the measurements through the upper 200m of the water column allow evaluation of the vertical distribution of phytoplankton, particles with little chlorophyll_a, and the concentration of dissolved colored material in the water column.

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